<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>js的书写位置</title>
</head>
<body>
    <div>hello world!1</div>
    <script type="text/javascript">
        alert("hello world!");
        document.write("hello world!");
        console.log("hello world!")
    </script>
</body>
</html>